British Prime Minister David Cameron says his country will introduce a resolution at the U.N. Security Council today, authorizing action to protect civilians in Syria's civil war. And it will surely be blocked by one of Syria's main allies, Russia. Still, that move is one in a series of necessary steps that could lead to a military strike on Syria. Today's development come as the Obama administration is trying to reassure the Kremlin that it still wants a negotiated solution to the civil war there.

The U.S. and Russia agreed in June to try to bring the warring factions to the negotiating table. Moscow says a military strike will now make that impossible. But as NPR's Michele Kelemen reports, the U.S. says it's still committed to this diplomatic effort, eventually.

MICHELE KELEMEN, BYLINE: This is the day U.S. and Russian diplomats were supposed to meet to try again to arrange a Geneva peace conference for Syria. The U.S. decided not to bother for the time being, but State Department spokesperson Marie Harf insists the meeting was just postponed, not cancelled.

MARIE HARF: We did not believe that this was right timing for this meeting. But again, we are working right now with the Russians to reschedule it at a time that makes more sense - hopefully in the very near future. And we'll continue to work with Russia and our international partners, again, because we are fully invested in this process.

KELEMEN: She says Secretary of State John Kerry has been in regular contact with his Russian counterpart Sergey Lavrov. In a news conference this week, Lavrov said he questioned Kerry about U.S. strategy in Syria and didn't get a very satisfying response. He's warning that a military strike would be a disaster and would make diplomatic efforts even harder. Even before the talk of U.S. military strikes, Lavrov says, the opposition showed no interest in compromising with the Assad regime.

SERGEY LAVROV: (Foreign language spoken)

KELEMEN: Why would they want to go to a conference, Lavrov says, when the regime's entire military structure is about to be bombed, and the opposition can, without any conference, take power in Damascus.

He seems to be brushing off U.S. assurances that any operation won't be about regime change.

But Lavrov said something else in that news conference that caught the ear of Andrew Weiss of the Carnegie Endowment for International Peace. Weiss points out that the foreign minister made clear that despite all of these concerns, Russia isn't going to war with anyone.

ANDREW WEISS: The Russians can sit back. And the Russians can be the Monday morning quarterback, in the I-told-you-so crowd. But the reality is that the Russians are not the biggest enabler of Assad. They provide a diplomatic umbrella. But we see with the apparent moves that the U.S. and other countries are making to respond to the WMD attack, that the path to military action does not run through the Security Council.

KELEMEN: So Russia won't have veto power over any planned military strike. Weiss was a Russia expert in the Clinton White House and remembers how relations were ruptured when the U.S. decided to take action in Kosovo, again working around Russia and the Security Council.

WEISS: It's entirely possible we're heading in that direction with the Russians. But at the same time, they can't relegate themselves to this role of just being the propaganda arm of the Assad government. And I think they're edging closer to that.

KELEMEN: Like Syria, Russia has been suggesting that the rebels were behind the chemical weapons attacks to provoke an international response. Syria's Foreign Minister Walid al-Muallem has been highlighting just how close the two countries are.

WALID AL-MUALLEM: (Foreign language spoken)

KELEMEN: Russian-Syrian relations are historic ones, going back decades, Muallem says, adding that diplomats and officials are in touch almost daily.

But Weiss, of the Carnegie Endowment, says Russia does have other interests in the region and wants respect. Particularly in the run-up to a major international summit, the G-20, which President Vladimir Putin is hosting in early September.

WEISS: If they stake out a position that is so inimical to ways that leading Western powers are viewing the situation on the ground in Syria, you can see other leaders deciding that they really don't want to be in the photo op. Whether that means other leaders stay home, or whether that means the atmosphere at the G-20 becomes really publicly acrimonious, is something the Russians have to weigh very carefully.

KELEMEN: President Obama is planning to go, but won't spend extra time in Russia to meet separately with Putin.